Heavy durable goods such as lawn and garden tractors, lawn mowers, boat motors, and engines, among other goods, present problems for packaging. Such machinery is generally difficult to pack, handle and store. Conventional corrugated containers have long been recognized as unsuited for packing such heavy, bulky goods. Wooden containers provide structural support and protection for the contained goods, but the weight, size and handling problems of such wooden containers limit their use. As a result, wood reinforced (cleated) corrugated paperboard boxes with mating wood pallet bases and wood top frames have been developed. Such an assembly is generally known as a pack.
The conventional wood cleated, corrugated box provides at least one interior wall with one or more wood reinforcement cleats vertically aligned. The wood cleats attach to the corrugated box in a conventional manner, such as with glue, staples or preferably a combination thereof. The corrugated paperboard body gives the container definition and maintains the position of the vertical wood cleats. The corrugated paperboard preferably is of sufficient strength to act as bracing to keep the wood vertical cleats erect. If the board is too light, it may rip during handling and shipment of stacked containers. This allows the stack to collapse in a sideways or trapezoidal manner. In some embodiments, special reinforcing filaments, or tear tapes are manufactured into the corrugated paperboard in a girth-wise direction to assist preventing such tearing and trapezoidal collapse of the packs.
The wood pallet forms a base which attaches to the paperboard box and supports the product packed therein. The top frame cooperates with the flaps of the corrugated box to close the container and provide a surface upon which another container may be stacked.
Durable goods are typically stacked in packs up to six units high for efficient utilization of warehouse space. The wood cleated corrugated paperboard box with a matching wood pallet base and wood top frame commonly achieves the necessary stacking or top load strength for shipping, handling, and storage of such heavy, durable goods. In particular, the wood vertical cleats attached to the side walls of the corrugated box have greater compression strength than the corrugated paperboard alone. Wood does not experience loss of strength during conditions of a high heat and humidity as does standard corrugated paperboard. Products packaged using wood cleated, corrugated paperboard boxes can typically be stacked higher with greater degree of safety than corrugated paperboard boxes.
The goods typically contained in such reinforced containers are heavy. For instance, garden tractors weighing up to 800 pounds or more are typically enclosed in such containers. Stacking requires that the top of the package be supported so that the upper units do not cause the lower units to collapse. The top support generally is provided by the wooden top frame positioned on top of the vertical wood cleats inside the corrugated box.
Conventional packaging of heavy equipment in a typical wood cleated pack first fastens the equipment to the pallet. The wood reinforced corrugated paperboard box is then placed over the equipment and slid down over the pallet. The corrugated paperboard box is stapled to the wood runners of the pallet in a conventional manner by a compressed air-driven staple gun. The top frame inserts into the upper portion of the corrugated body. The upper ends of the wood cleats receive and support the top frame. The top flaps of the box fold over the top frame. Staples and glue security attach the flaps to the top frame. Steel or plastic banding is often provided to gird the completed pack.
For a flange-style pack, the paperboard box is first positioned upside down and the pallet is inserted into the box to rest on the lower ends of the cleats. The flanges extending from the box fold over the bottom surfaces of the pallet. The flanges are stapled to the pallet to attach the pallet and the box together. The pack is then positioned right side up for receiving the product and the top frame.
An alternate method joins the corrugated box to the pallet with attaching strips. Such strips are glued and stapled to the bottom perimeter of the corrugated box side walls. Nails or narrow crown long-legged staples are driven through the box walls, the strips, and into the boards of the pallet. Such a method provides adequate joining of the box to the pallet to allow clamp truck handling while minimizing the risk of separation of the box from the pallet. This style further allows the packers to roll the tractor onto the base instead of hoisting and dropping the tractor into the box as is done with the flange-style pack described above.
While wood reinforced shipping containers have proven adequately effective for packaging heavy equipment, several problem exist. Among these are problems arising from use of conventional package handling equipment, such as fork lifts and clamp trucks. Generally, the use of fork lifts require that the shipping container include an external skid board below the container to provide clearance for the fork blades. This requires extra parts for the pallet, and increases the height of the container in which the product is stored. Such additional height is compounded in a high stack of containers and may result in failing to fully utilize the stackable dimensions of the truck or rail car. This results in fewer units in the load and a higher freight cost for shipping the manufactured product.
Clamp trucks use parallel vertical platens to handle packs. The platens squeeze against the sides of the pack. Clamp truck handling however encounters problems when the platens are not of sufficient size to engage the full depth of the package. The operator of the truck often attempts to maneuver the clamped platens toward the center-most area of the box walls. This produces an undesirable inwardly directed force on the box side walls and the wood vertical cleats. The corrugated paperboard may rip along the bottom where it attaches to the wood pallet. A worse consequence is failure of the wood vertical cleats which provide the stacking strength of the pack. The cleats may be knocked loose from the corrugated side walls, broken, or forced off the pallet surface on which they sit. Failure of the wood vertical cleats compromises the top load stacking strength. Damage to the container and the product may result. Use of a container with an undetected cleat failure may lead to the collapse of a five or six high stack of 800 pound tractors. Prevention of such side wall failure is important when handling and storing heavy equipment packed in such containers. On some known pallets, a cross member providing the pallet with structural support also supports the lower end of a box cleat. The cross member is positioned against a side of the cleat and resists dislodgment of the cleat by a force on the cleat in the direction of the cross member. This side support however does not prevent the cleat from splitting near its notched lower end. It also does not provide resistance to a transverse force such as that experienced when the clamp truck operator picks up the pack with the platters on the "wrong" sides.
As discussed, heavy equipment packed in wood reinforced containers often is handled in a variety of circumstances at the manufacturing plant, in transit, and at the retail sales store. Each facility may have different package handling equipment. For handling convenience, the package must provide sufficient bottom strength and fork entry clearance for fork truck handling. The pack must also have adequate side-to-side and end-to-end strength to allow clamp truck handling. Securing the wood cleated corrugated box to the pallet must provide sufficient strength so that when clamp trucks are used, the weight of the equipment on the pallet will not cause the pallet to separate from the box.
Generally, it is easier for a lift operator to stack and unstack packs in a warehouse with a clamp truck. This is because the operator can better see the position of the large platens against the side walls of a pack instead of attempting to place the blades of the fork truck in the relatively narrow openings of the pallet of a forkliftable pack. This is especially true when the operator is attempting to unstack packs at the upper end of a stack that may reach twenty (20) feet or more in height. Also, the difficulty in positioning one pack unit on top of another in a warehouse requires that the bearing surface of the top of the pack have increased capacity. Then, inexact placement of an upper pack in warehouse stacking or in stack shipment will not cause the upper packs to collapse the top of a lower pack and damage the contents. Shifting during transit, or improper stacking without supporting the tops of the lower packs, may result in one or more containers being crushed and stacks falling over, with resultant damage to the tractors and possible injury to personnel.
To provide top strength, typical cleated corrugated boxes include the wooden frame top which sits on the upper ends of the wood cleats. Special mating notches and grooves cut in the upper end of the cleats and in the ends of the top frame members cooperate to prevent the top frame from shifting off of the vertical cleats during handling and shipping of the pack. The top frame, locked onto the wood cleats, distributes the load of the upper packs onto a lower pack, provides protection to the vulnerable hood of a tractor (or to the contained item) and provides additional clamp truck strength against the side-to-side or end-to-end pressure exerted by the platens of a clamp truck.
These top wooden frames, however, have drawbacks and may themselves damage the tractor in the container. One problem with these top frames is that the size and weight is such that it is difficult for personnel on the assembly lines to lift the frame over the box side walls and position it on the vertical post. Often, these frames, due to the pack dimensions, contain up to 15 board feet of lumber, or more, and have a weight of 30 pounds or more. It is awkward for one person to handle such frames. The combination of the frame weight and size may cause the packer to have difficulties handling the frame and positioning it in the container. Accordingly, two or more persons are often required for packing a tractor in such a container.
An additional problem has been that the boards in the top frame occasionally break. Such breakage is sometimes caused by the force exerted by upper packs in a stack during transit or warehousing. In other circumstances, heavy containers fall through the top of the pack or break through the frame boards. Sometimes, the boards making up the frame are defective and unable to support the load for which the frame is designed. A knot in the wood particularly weakens a board. Broken boards are forced downward and scratch or dent the hood or other parts of the tractor the top frame was designed to protect.
It is also important that such wood reinforced packs be readily and easily handled for shipment from the box manufacturer to the user. The corrugated box must be fully collapsible for shipment. A box which is not collapsible incurs significant additional cost, including use of excessive space in both transit and warehousing and freight costs would be higher. For example, a typical 48 foot road van holds 48 set-up garden tractor boxes, whereas it will hold approximately 250 sets of knocked-down garden tractor packs.
Accordingly, there is a need in the container industry for a top support for wood cleated containers which overcomes the problems associated with the use of top wood frames for containers. There is also a need for a pallet which overcomes the problems arising from the use of a wood cleated corrugated body attached to a pallet.